How to prepare print files correctly
Vector graphics (curves) – the basis for screen printing and flexographic printing
As we most commonly use screen printing and flexographic printing, the supply of correct vector data is crucial for us.
What are curves (vectors)?
Vector graphics consist of geometric objects (lines and shapes) defined by mathematical formulas. They can be scaled up or down infinitely, and the image will always remain perfectly sharp. They are ideal for logos, text, lettering and icons (formats such as PDF, AI, EPS).
Common mistake: Simply opening a raster image (e.g. JPG) and saving it or exporting it to PDF format will not convert it into vectors. The image remains a raster; it is merely ‘embedded’ within the PDF file. To obtain vectors, the graphic must be redrawn (vectorised) manually or automatically in a graphics programme.
Raster (bitmap) graphics
Raster graphics can be used for digital printing on paper bags, and for DTF and DTG digital printing on cotton bags.
They have a fixed resolution (number of pixels). If you zoom in on a raster image, you will see individual squares (pixels). In short, the image loses its sharpness and becomes ‘pixelated’. You’ll often find this type of graphics in photographs and images saved in formats such as .JPG, .PNG, .TIF, etc.
Common mistake: Images downloaded from the web or social media are typically only 72 DPI. They look great on a mobile screen, but will appear blurred and ‘pixelated’ when printed. Low resolution cannot be artificially increased without a loss of quality – so always provide the original files in full print quality.
Specific requirements by technology:
Screen
printing Screen printing requires specific preparation: each individual colour in the design must have its own exposure film and its own printing screen.
In order to break down your artwork into these individual colour layers and ensure perfectly sharp edges during exposure, we require your data exclusively in vector format (vector graphics, most commonly in .PDF, .AI, .CDR or .EPS formats). Standard images (JPEG or PNG) cannot be used for screen printing, as they do not allow for the clean separation of colours required for the production of films and screens.
Colours must be defined according to the Pantone C colour guide.
Flexographic
printing Flexographic printing requires the production of a printing plate. The plate is a flexible, raised mould that acts as a stamp, transferring ink directly onto the material being printed. To produce it, the print data must be supplied exclusively as curves (vector graphics, most commonly in .PDF, .AI, .CDR or .EPS formats). Unfortunately, standard images or photographs (such as JPEG or PNG) cannot be used with this type of technology.
**Plate price
The production of a printing plate is a one-off investment (for repeat printing without changes, the plate is reused until it wears out). The price of the plate depends on its final dimensions – that is, the area actually occupied by your artwork.
Colours must be defined according to the Pantone U colour chart.
Digital printing
If your design contains photographs or complex shaded graphics, your files will be in ‘raster’ (bitmap) format. For this type of data, the correct print resolution is key to achieving a perfect result.
The resolution should be at least 300 DPI. Images must have this resolution at their actual print size (1:1 scale). The most common formats are JPG, PNG, PSD and PDF.
All data must be converted to the CMYK colour space.
Be careful with images from the internet: graphics downloaded from the web or social media typically have a resolution of only 72 DPI. They look great on a mobile phone screen, but will appear blurred and ‘pixelated’ when printed. Low resolution cannot be artificially increased without a loss of quality – therefore, always supply the original data in full print quality.